This invention relates to specimen collection fluids, and more particularly to a specimen collection fluid for the treatment of blood and/or bone marrow specimens to be used for immunohaematological analysis.
The current methods of immunohaematological analysis of specimens obtained from patients suffering from haematological malignancies and immunological disorders such as AIDS require the specimen to be collected into a sterile blood collection tube containing an appropriate amount of a specimen collection fluid, which is usually an anticoagulant solution. However, several studies have reported that collection of peripheral blood or bone marrow requires that such specimens should be processed within a 6, 18 or 24 hour period, depending on the test involved, to ensure antigen stability and no deterioration of sample integrity. Due to these strict time limitations, the transportation of a specimen to the analysis site is almost always required to be carried out on a very urgent basis. If analysis is delayed, for example, if a patient""s specimen is obtained on a weekend or a bank holiday, or a specimen is transported from one country to another, it may not be in a suitable condition when finally submitted to analysis, and a further specimen may need to be taken.
Stabilisation fluids presently available require the collection of anticoagulated blood and then the addition of 1 ml of specimen collection fluid to 1 ml of the anticoagulated blood specimen, resulting in a considerable dilution of the specimen, which makes the results of the subsequent immunohaematological analysis very difficult to interpret.
By a xe2x80x9cspecimen collection fluidxe2x80x9d in this specification is meant a fluid which is mixed, in use, with a specimen to be analyzed to provide the specimen with improved storage properties and which remains in contact with the specimen during storage without substantially interfering with the subsequent analysis.
Commercially available stabilisation fluids also give poor results with leukemics.
In international patent applications nos WO 95/01796 and WO 95/27203 there are described stabilised cell preparations prepared by treating the cells with a stabilising agent comprising a heavy metal compound, particularly a transition metal salt. The stabilising agent may also comprise an effective amount of an aldehyde. The stabilised cell preparations can be stabilised whole blood preparations for use in quality control procedures for analytical techniques.
It is an object of the invention to provide an improved specimen collection stabilisation fluid suitable for imunohaematological analysis specimens, which in preferred embodiments, can allow the collection of a specimen directly into a specimen collection container containing the stabilisation fluid.
It is also an object of the invention to provide a specimen collection container comprising an improved specimen collection fluid.
It is a further object of the invention to provide a method of collection of specimens, for example, for immunohaematological analysis, which comprises contacting the specimens with a novel specimen collection fluid providing improved storage properties without substantially interfering with the analysis.
In a first aspect the invention provides a specimen collection fluid, for example, for immunohaematological analysis specimens, which comprises a sterile buffered aqueous solution comprising an aliphatic aldehyde, at a molar concentration of 0.15M to 3.4M, one or more heavy metal salts, at a total molar concentration of 0.2xc3x9710xe2x88x923M to 0.2M, and, preferably, an anticoagulant, at a molar concentration of 0.27M to 0.45M, the solution having a pH in the range of 6.8 to 8.0.
It will be understood that in the case where blood already in an anticoagulated state is to be used, an anticoagulant is optional.
In another aspect the invention provides a specimen collection container for the reception of specimens for analysis, which contains a stabilising amount of a specimen collection fluid comprising a sterile aqueous solution comprising an aliphatic aldehyde, at a molar concentration of 0.15M to 3.4 M, one or more heavy metal salts, at a total molar concentration of 0.2xc3x9710xe2x88x923M to 0.2M, and an anticoagulant, at a molar concentration of 0.27M to 0.45M, the solution having a pH in the range of 6.8 to 8.0.
In a further aspect the invention provides a method of collection of specimens for immunohaematological analysis and/or other analytical techniques, for example such as histopathological analysis, which comprises contacting the specimen with a specimen collection fluid comprising a sterile aqueous solution comprising an aliphatic aldehyde, at a molar concentration of 0.15M to 3.4M, one or more heavy metal salts, at a total molar concentration of 0.2xc3x9710xe2x88x923M to 0.2M, and an anticoagulant, at a molar concentration of 0.27M to 0.45M, the solution having a pH in the range of from 6.8 to 8.0.